The HIV Center for Clinical and Behavioral Studies at the New York State Psychiatric Institute and Columbia University is committed to inter- disciplinary research on behavioral manifestations critical to HIV infection and HIV disease progression. We propose to continue our research for a second five year period, building on a strong record of accomplishments; of stimulating new research in HIV/AIDS through consultation and collaboration; and of providing training and exchange with colleagues in local, national, and international communities. We are proposing six research projects: (1) Determinants of Sexual Problem Behaviors in Childhood; (2) HIV Risk and Coming-Out among Gay and Lesbian Adolescents; (3) AIDS Prevention for Girls in Therapy for Depression; (4) Sexual Risk Behavior and Behavior Change in Heterosexual Women and Men; (6) Primary Prevention for Male HIV-Serodiscordant Couples; and (7) Critical Time Intervention to Reduce HIV Risk Behaviors among Homeless Mentally Ill Individuals. Five cores will provide expertise to Center investigators and affiliated colleagues. Three of them are research cores directly linked to the research projects: (1) Psychosocial/Qualitative Assessment; (2) Psychosexual Assessment; and (7) Statistics, Epidemiology, and Data Management. Core 5 (Information Exchange) and Core 8 (Ethical, Policy, and Legal) will dynamically connect the HIV Center to the local, national, and international communities. The significance of the research proposed is multifold: (1) It will advance our understanding of the determinants of sexual risk behavior for HIV infection and for behavior change among heterosexual women and men. (2) It will further our knowledge of developmental principles of sexual risk behavior during childhood and adolescence in the context of gender, age, sexual orientation, and mental illness. (3) We will test new intervention approaches for HIV infected women and men at the level of the individual and the (serodiscordant) couple. (4) This Center will address multiple HIV-related problems and attempt to change sexual risk behavior among the homeless mentally ill. (5) We will make methodological contributions to HIV research in psychosexual assessment and statistical/epidemiological techniques. (7) The Center will provide a forum for ethical, legal, and policy debate. (8) We will further develop sophisticated media-based intervention tools to increase the effectiveness of behavior change strategies at the community level.